This improvement in mean particle size was related to the decrease of alginate concentration and subsequent reduction in sodium alginate chains and number of the carboxylate, ether and hydroxyl groups that are jointed to the calcium cation. It has been reported that the main factor for creating nanoparticles is the tendency of functional groups of alginate chains especially carboxylate groups to create complex structures with calcium ions. The increase of alginate concentration affording more functional groups can gather around calcium crosslinking agent and therefore further layers of alginate chains can join the calcium cations; in conclusion, the size of nanoparticles increases with increasing of alginate concentration.